This invention relates generally to sluice gates of the type used in water control and sewage systems.
In one type of conventional sluice gate, for example that disclosed in U.S. Pat. No. 2,643,521 and British Pat. No. 685,012, a metal frame surrounds an opening and a metal gate disc is mounted on the frame for movement between open and closed positions. The gate disc and the frame have metal seat facings. Wedges on the gate disc cooperate with bosses on the frame to force the seat facings of the gate disc against the seat facings of the frame as the gate disc moves into the closed position. Although this type of sluice gate is entirely acceptable for a wide range of applications, experience has indicated that some leakage must be expected because dirt and grit will become trapped between the metal seat facings, and also because it is often difficult to achieve or maintain an optimum setting of the wedges relative to their associated bosses.
A number of attempts have been made at solving this leakage problem. For example, in U.S. Pat. No. 3,237,915, the gate disc is moved into and out of sealing engagement with a seat facing on the frame by means of a system of bell cranks pivotally responsive to vertical adjustment of the gate disc. This type of arrangement has failed to gain widespread acceptance, due in large part to the high costs and maintenance difficulties associated with the complicated crank-type closure mechanism.
Another attempted solution to the leakage problem is disclosed in U.S. Pat. No. 4,070,863 where the gate disc is provided with a seal which is extruded into sealing engagement with a metal seat facing on the frame. This extrusion is achieved by means of a seal retainer which surrounds the seal and which carries wedges arranged to cooperate with bosses on the frame. This arrangement also suffers from a relatively complicated and expensive construction.
In another known sluice gate assembly, a metal frame surrounds an opening and a metal gate disc is mounted for movement between open and closed positions along fixed guides on the frame. The gate disc carries a resilient deformable seal which cooperates in sealing engagement with a plastic seat face on the frame. The sealing interface between the two seal components is arranged at an angle relative to the line of travel of the gate disc so that as the gate disc slides along the guides into the closed position, the seal components are gradually brought together to affect a substantially leakproof seal. While this arrangement represents a decided improvement over prior attempts at eliminating or at least minimizing leakage, still certain problems remain. For example, because the guides are fixed relative to the frame, the degree of deformation of the seal on the gate disc is not adjustable. Thus, as wear occurs, or in the event that the deformable seal takes on a "set", leakage will result, thereby necessitating replacement of the deformable seal. Such replacements entail dismantling and reassembly of the sluice gate in the field. The objective of the present invention is to avoid this problem by providing a simple yet effective means for adjusting the degree of seal deformation without dismantling the sluice gate assembly. Such adjustments may be performed by the manufacturer during initial assembly of the sluice gate components, and by the user under field conditions without taking the gate out of service.